In the related art, an optical module including a photoelectric conversion element (light-emitting element, light-receiving element or both) is used in optical communications using an optical transmission member such as an optical fiber and a light waveguide. In an optical module, an optical receptacle that is disposed between a photoelectric conversion element and an optical transmission member and is configured to optically couple the photoelectric conversion element and an end surface the optical transmission member is used. Optical modules are classified into a transmitting optical module having a transmitting capability and a receiving optical module having a receiving capability, and a transmitting and receiving optical module having both a transmitting capability and a receiving capability.
In addition, in optical modules designed for optical communications, it is necessary to attenuate the intensity of light emitted from the optical receptacle in view of safety. For this reason, an optical filter for attenuating the intensity of light emitted from the optical receptacle is used in transmitting optical modules in some situation (see, for example, PTL 1).
FIG. 1 is a sectional view illustrating a configuration of optical receptacle 1 disclosed in PTL 1. Optical receptacle 1 disclosed in PTL 1 includes optical receptacle main body 2 and optical filter 3 (e.g. a light attenuation filter). As illustrated in FIG. 1, optical receptacle main body 2 includes lens surfaces 4 arranged in a line at even intervals on the bottom surface of optical receptacle main body 2, and optical surface 5 disposed facing away from lens surface 4. Optical filter 3 is disposed on a part of optical surface 5. Optical receptacle 1 disclosed in PTL 1 is used in the state where a photoelectric conversion device including a plurality of light-emitting elements and a plurality of light-receiving elements is disposed on lens surface 4 side, and a plurality of optical transmission members are disposed on optical surface 5 side. In optical receptacle 1 disclosed in PTL 1, optical filter 3 is disposed on the light path of light emitted from light-emitting element and entering the optical transmission member, and thus the intensity of light emitted from optical receptacle 1 toward the optical transmission member can be attenuated.